Many useful and attractive man-made materials are in common use for the top surfaces of cooking appliances and for kitchen counter-top cooking units (cooktops). Popular materials include enameled steel and ceramic glass materials such as "Ceran".TM. made by Schott Glaswerke of Germany. Other materials such as "Formica".TM. and DuPont "Corian".TM. plastic-type material are commonly used for food preparation countertops. However, the natural beauty, the hard surface resistant to scratching and denting, ease of cleaning, and the impermeability of natural stone make it a desirable material with which to fabricate cooktops and adjacent areas of countertops. This is especially true of natural granite. Each individual counter-top cooking unit made of granite has a unique natural appearance determined by its natural visual texture and the combinations of grain sizes and colors formed by nature. It is also useful for a cooking appliance to have a continuous extension of its top surface to serve as a food preparation surface area of natural stone. A cool stone surface is especially useful in the preparation of pastry for baking.
Heretofore, custom counter-top cooking appliances using natural stone have been relatively expensive due to the cost of procuring natural stone which is cut and polished to fit, and due to the skills required to install stone. A more troublesome problem, however, has been the tendency of natural stone to crack and fracture when subjected to thermal stresses. What is needed to improve the usefulness of natural stone cooktops is a natural stone cooktop surface with improved strength (especially improved tensile and flexural strength), with resultant improved resistance to cracking and fracture. A natural stone countertop cooking appliance that is relatively easy to install, to custom-fit to a kitchen space, and to equip with custom heating-element arrangements is also needed. A most useful natural stone cooktop would be one that is readily made to accommodate various types and sizes of heating elements. Commercial viability of natural stone cooktops requires avoiding excessive weight and excessive cost to the user for procurement and installation of natural stone.